The present invention is directed to a condenser for an air conditioning system, and more particularly, to an optimal condenser coil arrangement which provides high condenser airflow efficiency even when either of two air inlets is completely obstructed.
Previous condenser have had various coil arrangement when viewed from a longitudinal end of the condenser housing. Typically air inlets are provided on either side of the condenser housings with coils located within and fans located on top of the housing so that air enters from the sides, passes over condenser coils and exits upwardly through the fans. Previous condenser coil arrangements have suffered airflow efficiency losses approaching 50% whenever either of the side air inlets is completely obstructed, and have suffered proportional airflow efficiency reduction when either of the side inlets is partially obstructed.
For instance in a "U" shaped coil arrangement such as shown in U.S. Pat. No. 3,857,253, air enters from either side of the condenser housing either directly through the upright legs of the "U" or through air inlets located below the legs of the "U". After entering the air inlets, the air makes an abrupt 90 degree turn and passes through a condenser coil forming the base of the "U". This abrupt 90 degree turn results in an uneven air distribution and variable face velocity across the condenser forming the base of the "U". The bulk of the airflow is concentrated at the central portion of the "U"'s base. Should an obstruction such as a wall or another condenser be placed parallel to either side of the condenser so as to block the air inlets on that side, the loss of airflow coupled with the inefficiencies of the abrupt 90 degree turn result in an overall reduction in airflow efficiency approaching 50%.
Another condenser coil arrangement can be seen in applicant's publication "Air Cooled Condensers, 20-120 Tons". This publication shows a "V" arrangement where air enters from either side, passes through one or the other of the legs of the "V", and exits in an upward direction. The legs of the "V" extend essentially from the top to the bottom of the condenser housing. If an obstruction blocks either air inlet, air does not flow through that particular leg of the "V". Consequently, airflow efficiency is reduced by 50% if the obstruction completely blocks the inlet, and is reduced in proportion to the obstruction's distance from the air inlet if the obstruction does not completely block the inlet.
A third condenser coil arrangement presently utilized is a "deep W" which includes a pair of "V" coils forming a "deep W" extending from the housing top to the housing bottom. The outside legs of the "deep W" are similar to the "V" arrangement in that airflow enters from the sides of the housing passes over the coils and exits in an upward direction through the condenser fans. The inner legs of the "deep W" differ in that airflow enters from at least one of the longitudinal ends of the condenser housing through the relatively small triangular area formed between the housing base and the inner legs of the "deep W" This relatively small triangular area has limited airflow efficiency across the condenser coils forming the inner legs of the "deep W" arrangement. If an obstruction blocks or retards airflow from either of the side inlets across one of the exterior legs of the "deep W", airflow efficiencies can approach 50% reduction when the inefficient airflow across the inner legs of the "deep W" is also accounted for.
The primary solution taken previously to preventing reduced airflow efficiencies is to ensure a minimum clearance around the condenser housings. This clearance is recommended to be at least 6 feet. Often this is not feasible in view of the typical location of a condenser housing on a roof top. Sound barriers, decorative sight barriers, pit locations, walls, other condenser housings, or air downflow geometries often prevent optimal location and clearance around the condenser housings.